The present invention is directed to methods and apparatuses for measuring the alignment of rotational bodies, and more particularly, to methods and apparatuses for measuring the alignment of rotational bodies using a laser and a sensor mounted onto the rotational body.
In manufacturing and other industries, machines utilizing a variety of rollers, gears, shafts, axles and other rotational bodies are commonly used. The axes of the various rotating bodies must be aligned to ensure proper functioning of the machines. Of particular interest for alignment purposes are out-of-square measurements (the deviation of the rotational axis of the rotational body with respect to a vertical plane passing through the rotational axis) and out-of-level measurements (the deviation of the rotational axis of the rotational body with respect to a horizontal plane passing through the rotational axis). In order to measure out-of-square of a particular rotational body, typically a reference plane is established, and a measurement device is passed across the face of the rotational body (i.e., along the length of the rotational body). The reference plane may be defined by a laser, a wire, a rope, or the like. The measurement device cooperates with mechanical or electronic distance-measuring apparatuses as the measurement device is passed along the face of the rotational body to detect the out-of-square or out-of-level measurements relative the reference plane. Alternately, the distance between the reference plane (e.g., a taut string) and various points on a rotational body may be manually measured to calculate out-of-level.
However, these measurement methods require access to the face of the rotational body, and are therefore ineffective when the rotational body is surrounded by other components or is otherwise inaccessible. In this case, the alignment of the rotational body cannot be measured, or the machine must be partially or fully disassembled to gain access to the rotational body. However, the disassembly of the machine is inconvenient and time consuming. Furthermore, disassembly of the machine alters the machine""s operating characteristics, and the resulting measurements may not present a true picture of the alignment of the rotational body during operation. Furthermore, taking manual measurements is time consuming and often imprecise.
Accordingly, there is a need for a method and an apparatus for detecting the alignment of a rotational body that can quickly and accurately measure the out-of-square and out-of-level of the rotational body without requiring access to the face of the body.
The present invention is a method and apparatus for measuring the alignment of rotational bodies that is quick and accurate. The invention uses real-time laser measurements to measure out-of-square and out-of-level quickly and accurately, and can carry out such measurements without access to the front surface of the body. Furthermore, because the measurements are displayed in real time, the rotational body may be manually adjusted, and the system provides immediate feedback such that the rotational body can be located in the desired position. The present invention may also be used to measure both out-of-square and out-of-level without changing the location or setup of measuring equipment.
In a preferred embodiment, the invention is a method for determining the alignment of a rotational body. The method includes the steps of locating a sensor on an outer surface of a rotational body, targeting a reference laser beam at the sensor such that the reference laser beam intersects the sensor at a reference coordinate, and recording the reference coordinate. The method further includes rotating the rotational body about the axis of rotation of the rotational body, targeting a measurement laser beam at the sensor such that the measurement laser beam intersects the sensor at a measurement coordinate, and comparing the reference coordinate and the measurement coordinate.
Accordingly, it is an object of the present invention to provide a method and apparatus for measuring the alignment of rotational bodies that is quick and accurate. Other objects and advantages of the present invention will be apparent from the following description and the accompanying drawings.